If you're on a personal connection you can run an anti-virus scan on your device to make sure it's not affected by malware.

During high-traffic product releases we have extra security in place to prevent bots entering our site. If you're on a shared network, you could ask the system administrator to run a scan looking for misconfigured or infected devices across the network. Discover long and short-sleeve t-shirts in signature red hues with burgundy, maroon and bright red tones. Something in your setup must have triggered our security system, so we cannot allow you onto the site.Choose from the array of men’s red t-shirts in block colourways or sporting playful prints and patterns.

You could also check if there are any scripts, like ad blockers, running in your browser and disable them.